U.S. patent number 11,071,521 [Application Number 14/854,163] was granted by the patent office on 2021-07-27 for internal ultrasound assembly with port for fluid injection.
This patent grant is currently assigned to Muffin Incorporated. The grantee listed for this patent is Muffin Incorporated. Invention is credited to Neal E. Fearnot, William J. Havel, Peter S. McKinnis, Sarah Robbins, Yun Zhou.
United States Patent |
11,071,521 |
Havel , et al. |
July 27, 2021 |
Internal ultrasound assembly with port for fluid injection
Abstract
There are disclosed embodiments of devices and methods for
imaging the inside of a body part, particularly a blood vessel. In
particular embodiments, a catheter has a tip chamber, within which
is an ultrasound transducer mounted on a pivot mechanism, a motor
for turning the transducer, and an implement for pivoting the
transducer. Examples of such an implement are a linear motor, a
shaft or filament, and the pivot mechanism may be biased to return
to a base position when the implement is not pivoting the
transducer. In other embodiments, a mirror reflecting ultrasound
signals from the transducer may be rotated and/or pivoted, using
similar mechanisms.
Inventors: |
Havel; William J. (West
Lafayette, IN), Robbins; Sarah (Lafayette, IN), McKinnis;
Peter S. (Carrboro, NC), Zhou; Yun (West Lafayette,
IN), Fearnot; Neal E. (West Lafayette, IN) |
Applicant: |
Name |
City |
State |
Country |
Type |
Muffin Incorporated |
West Lafayette |
IN |
US |
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Assignee: |
Muffin Incorporated (West
Lafayette, IN)
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Family
ID: |
51530485 |
Appl.
No.: |
14/854,163 |
Filed: |
September 15, 2015 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160000405 A1 |
Jan 7, 2016 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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PCT/US2014/023088 |
Mar 11, 2014 |
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61787768 |
Mar 15, 2013 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B
8/4461 (20130101); A61B 8/12 (20130101); A61N
7/022 (20130101); A61B 8/4281 (20130101); A61B
8/4272 (20130101); A61B 8/0891 (20130101); A61B
8/445 (20130101); A61N 2007/0082 (20130101); A61B
1/00064 (20130101); A61N 2007/0043 (20130101); Y10T
29/49005 (20150115) |
Current International
Class: |
A61B
8/00 (20060101); A61B 8/12 (20060101); A61B
1/00 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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06-209939 |
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Aug 1994 |
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JP |
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1994-209929 |
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Aug 1994 |
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JP |
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10-262974 |
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Oct 1998 |
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JP |
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1988-262974 |
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Oct 1998 |
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JP |
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2000-126184 |
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May 2000 |
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JP |
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2001-046375 |
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Feb 2001 |
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JP |
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2004/129697 |
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Apr 2004 |
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JP |
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2007-267998 |
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Oct 2007 |
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JP |
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WO 2012/061643 |
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May 2012 |
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WO |
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Other References
International Search Report and Written Opinion issued in
PCT/US2013/064570, dated Jan. 24, 2014. cited by applicant .
International Search Report and Written Opinion issued in
PCT/US2013/064579, dated Jan. 23, 2014. cited by applicant .
International Search Report and Written Opinion issued in
PCT/US2013/064606, dated Jan. 8, 2014. cited by applicant .
International Search Report and Written Opinion issued in
PCT/US2013/064611, dated Jan. 28, 2014. cited by applicant .
International Search Report and Written Opinion issued in
PCT/US2013/064618, dated Jan. 24, 2014. cited by applicant .
International Search Report and Written Opinion issued in
PCT/US2013/078245, dated Apr. 25, 2014. cited by applicant .
International Search Report and Written Opinion issued in
PCT/US2014/023088, dated Aug. 18, 2014, 14 pgs. cited by applicant
.
International Search Report and Written Opinion issued in
PCT/US2014/023092, dated Aug. 12, 2014, 16 pgs. cited by applicant
.
International Search Report and Written Opinion issued in
PCT/US2014/058269, dated Jan. 9, 2015, 17 pgs. cited by
applicant.
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Primary Examiner: Fernandez; Katherine L
Assistant Examiner: Kellogg; Michael S
Attorney, Agent or Firm: Woodard, Emhardt, Henry, Reeves and
Wagner LLP
Parent Case Text
STATEMENT OF RELATED APPLICATIONS
This application is a continuation of PCT/US2014/023088, filed Mar.
11, 2014, which claims the benefit of priority of U.S. Provisional
Patent Application Ser. No. 61/787,768 filed Mar. 15, 2013, each of
which is incorporated herein by reference in its entirety.
Claims
What is claimed is:
1. An apparatus for ultrasound procedures, comprising: a transducer
for emitting and/or receiving ultrasound signals, the transducer
being within a chamber, the chamber defined at least partially by a
wall and a seal, the wall forming an acoustic window for
transmission of the ultrasound signals and the seal engaging the
wall; a motor operatively connected to the transducer, wherein the
seal abuts the motor and extends across the entire width of the
chamber so as to separate the motor from the chamber; an injection
port communicating with the chamber adapted for passing coupling
media through and into the chamber; and an exhaust port
communicating with the chamber through which gas within the chamber
can be exhausted from the chamber when the coupling media is
inserted into the chamber, wherein at least one of the injection
port and the exhaust port extends through the wall, and the exhaust
port does not pass through the seal; wherein the exhaust port
extends through the wall from a first point on an interior surface
of the wall to a second point on an exterior surface of the wall,
wherein the first point is within the chamber and the second point
is proximal of the seal with respect to a longitudinal axis of the
chamber.
2. The apparatus of claim 1, wherein the injection port comprises a
flexible insert fixed with respect to the wall, the insert
permitting insertion of a needle through it and thereafter
providing a leak-tight seal when the needle is removed from it.
3. The apparatus of claim 2, wherein the insert is placed at a
forward-most tip of the chamber.
4. The apparatus of claim 1, wherein the chamber is attached to or
part of an elongated tubular housing having an internal surface and
an external surface, and wherein the injection port comprises a
lumen opening into the chamber and extending through at least part
of the elongated tubular housing between the internal surface and
the external surface.
5. The apparatus of claim 4, wherein at least part of the lumen is
within a tube separate from the housing.
6. The apparatus of claim 4, wherein the lumen opens into the
chamber at a location not faced by the transducer.
7. The apparatus of claim 1, wherein the exhaust port comprises a
valve fixed with respect to the wall.
8. The apparatus of claim 7, wherein the valve is placed in the
wall at a location not faced by the transducer.
9. The apparatus of claim 1, wherein the injection port is located
opposite and facing the seal.
10. The apparatus of claim 1, wherein the injection port is located
adjacent the seal.
11. The apparatus of claim 1, wherein the exhaust port is located
adjacent the seal.
12. The apparatus of claim 1, wherein the injection port and the
exhaust port are located diametrically opposed from each other.
13. The apparatus of claim 1, wherein the wall includes an interior
and an exterior surface, and the seal engages the interior surface,
and wherein at least one of the injection port and the exhaust port
connect to a flow path exterior of the seal.
14. The apparatus of claim 1, wherein the exhaust port extends
through the wall, the exhaust port including a valve within the
wall.
15. An apparatus for ultrasound procedures, comprising: a
transducer for emitting and/or receiving ultrasound signals, the
transducer being within a chamber, the chamber defined at least
partially by a wall and a seal, the wall forming an acoustic window
for transmission of the ultrasound signals and the seal engaging
the wall; an injection port communicating with the chamber adapted
for passing coupling media through and into the chamber; and an
exhaust port communicating with the chamber through which gas
within the chamber can be exhausted from the chamber when the
coupling media is inserted into the chamber, wherein the exhaust
port extends through the wall from a first point on an interior
surface of the wall to a second point on an exterior surface of the
wall, wherein the first point is within the chamber and the second
point is proximal of the seal with respect to a longitudinal axis
of the chamber.
16. The apparatus of claim 15, further comprising a motor
operatively connected to the transducer, wherein the seal abuts the
motor and extends across the entire width of the chamber so as to
separate the motor from the chamber.
17. The apparatus of claim 15, wherein at least one of the
injection port and the exhaust port extends through the wall, and
the exhaust port does not pass through the seal.
18. The apparatus of claim 15, wherein at least one of the
injection port and the exhaust port are located adjacent the
seal.
19. The apparatus of claim 15, wherein the wall includes an
interior and an exterior surface, and the seal engages the interior
surface, and wherein at least one of the injection port and the
exhaust port connect to a flow path exterior of the seal.
Description
The present disclosure relates to structure and methods in medical
uses of ultrasound. In particular, this disclosure relates to
preparation of medical ultrasound devices.
BACKGROUND
In using ultrasound for imaging, therapy or other medical uses,
ultrasound energy or waves are transmitted through a medium and can
reflect, scatter or otherwise attenuate when they reach a surface
or border having a significant difference in acoustic impedance.
For example, in ultrasound imaging of the human body, ultrasound
waves may be applied externally (e.g. by placing a transducer on
the skin) or internally (e.g. by placing a transducer within a
vessel or organ), and travel through the body's internal fluids,
which is a large proportion of water. When the waves strike a bone,
organ or other body portion that provides an acoustic
interface--i.e., a border of two significantly different acoustic
impedances--then the waves are reflected or otherwise attenuated. A
transducer (which may be the same transducer that supplied the
ultrasound waves or another) receives the reflected or attenuated
waves, and an image of a portion of the body can be generated.
An external transducer is placed against the skin with a gel useful
as a coupling medium so that little or no reflection or other
attenuation from the boundary between the air over the patient and
the skin occurs. When a transducer is placed within the body,
commonly it is inside a protective envelope, such as a tube,
catheter or similar housing or enclosure. The material of such an
envelope may be selected for its similarity in acoustic impedance
to that of bodily fluids, so that there is little or no attenuation
as ultrasound waves travel from that material to the fluids or
tissues of the body. The inner pocket or volume of the body within
which the transducer is placed needs a coupling medium having an
acoustic impedance similar to that of the envelope material and the
body's fluids, to allow maximum transmission. Without such a
medium, e.g. if the inside of the body simply includes air or
another gas, significant reflection or other attenuation will occur
when the ultrasound energy from the transducer hits the boundary
where the gas meets the material of the envelope. Suitable coupling
media include biocompatible fluids such as saline, oils such as
mineral oil or castor oil, alcohols, and other fluids.
Of course, some coupling media (e.g. saline) can be corrosive over
time, particularly of metallic materials. If a corrosive coupling
medium is to be used, a drawback is that degradation of part(s) of
the transducer or other aspects of the device (e.g. structure used
to turn or move the transducer) may occur. An unacceptably short
shelf life for the product may thus result with such media. Thus,
the relatively low-cost medium of saline has significant downside
to a practical internal transducer product.
Embodiments of internal transducer products using piezoelectric
motors to turn or otherwise move a transducer have also been
suggested. Applicable piezoelectric motors generally need dry
conditions to operate, as they require a high friction contact area
between a stator and a clutch. If fluid touches that contact area
or interface, the friction will be substantially reduced, thereby
also reducing the torque output of the motor Accordingly, in such
embodiments to prevent fluid from contacting the motor a seal is
included between the motor and the transducer, to prevent leakage
of the coupling medium from the volume around the transducer toward
the motor. Such seals can fail over time, which is one potential
factor in shelf life for such products.
SUMMARY
Among other things, there are shown embodiments of apparatus for
ultrasound procedures that include a transducer for emitting and/or
receiving ultrasound signals, the transducer being within a sealed
chamber that is defined at least partially by a wall forming an
acoustic window for transmission of ultrasound signals. An
injection port communicates with the chamber through which coupling
media is inserted into the chamber, and an exhaust port
communicates with the chamber through which gas within the chamber
is exhausted from the chamber when coupling media is inserted into
the chamber.
In particular examples, the injection port includes a flexible
insert fixed with respect to the wall, the insert permitting
insertion of a needle through it and thereafter providing an
airtight seal when a needle is removed from it. Such an insert may
be placed at a forward-most tip of the chamber. In other examples,
the chamber is attached to or part of an elongated tubular housing
having an internal surface and an external surface, and the
injection port includes a lumen opening into the chamber and
extending through at least part of the housing between the internal
surface and the external surface. At least part of the lumen may be
within a tube separate from the housing. The lumen can open into
the chamber at a rearward-most portion of the chamber.
Embodiments are disclosed in which the exhaust port includes a
valve fixed with respect to the wall. The valve may be placed in
the wall at a rearward-most portion of the chamber. Other
embodiments may have the chamber attached to or part of an
elongated tubular housing having an internal surface and an
external surface, with the exhaust port including a lumen opening
into the chamber and extending through at least part of the housing
between the internal surface and the external surface. For example,
at least part of the lumen may be within a tube separate from the
housing. The lumen can open into the chamber at a rearward-most
portion of the chamber.
Such devices can include a motor (one or more) operatively
connected to the transducer, and a seal between the motor and the
transducer and fixed to the wall, the seal defining a rearward
boundary of the chamber. Particular examples have the injection
port located opposite and facing the seal. Other examples have one
or both of the injection port and exhaust port located adjacent the
seal. Embodiments in which the injection port and the exhaust port
are located diametrically opposed from each other are also
shown.
Methods for preparing and using devices for ultrasound procedures
are also disclosed. For example, such methods can include injecting
a coupling media into a sealed chamber, the chamber defined at
least partially by a wall forming an acoustic window for
transmission of ultrasound signals, and the chamber having within
it a transducer for emitting and/or receiving ultrasound signals.
The injecting can include moving the coupling media through an
injection port that communicates with the chamber, and during the
injecting, gas within the chamber prior to the injecting is forced
out of the chamber through an exhaust port. The injecting can
continue until a sufficient amount of coupling medium is injected,
e.g. the coupling medium displaces substantially all of the gas.
Particular examples of the injecting include inserting a needle
through the injection port and passing the coupling medium through
the needle and into the chamber. Other examples of the injecting
include passing the coupling medium through a lumen in a tube, at
least part of the tube being within a housing of the device. In
embodiments in which the exhaust port includes a valve, during the
injecting gas within the chamber prior to the injecting may be
forced out of the chamber and exterior of the device through the
valve. Where the exhaust port includes a lumen in a tube, at least
part of the tube being within a housing of the device, during the
injecting gas within the chamber prior to the injecting may be
forced out of the chamber through at least part of the lumen.
These and other embodiments are discussed further below.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a part cross-sectional view of an embodiment of a device
for use in ultrasound procedures.
FIG. 1A is a part cross-sectional view of an embodiment of a device
like that of FIG. 1 for use in ultrasound procedures.
FIG. 1B is a part cross-sectional view of an embodiment of a device
like that of FIG. 1 for use in ultrasound procedures.
FIG. 1C is a cross-section taken along the lines 1C-1C in FIG. 1B
and viewed in the direction of the arrows.
FIG. 2 is a partial perspective view of the embodiment of FIG.
1.
FIG. 3 is a part cross-sectional view of an embodiment of a device
for use in ultrasound procedures.
FIG. 3A is a part cross-sectional view of an embodiment of a device
like that of FIG. 3 for use in ultrasound procedures.
DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS
For the purposes of promoting an understanding of the principles of
the disclosure, reference will now be made to the embodiments
illustrated in the drawings and specific language will be used to
describe the same. It will nevertheless be understood that no
limitation of the scope of the claims is thereby intended, such
alterations and further modifications in the illustrated
embodiments, and such further applications of the principles of the
disclosure as illustrated therein being contemplated as would
normally occur to one skilled in the art to which the disclosure
relates.
Referring now generally to the drawings, there is shown an
embodiment of a device 20 for application of ultrasound internally
to a patient. As particular examples, device 20 is or is part of a
device or system for imaging, such as for intravascular ultrasound
(IVUS) imaging. Other embodiments can include devices for
therapeutic or diagnostic uses within the body, or for ultrasound
devices used outside of the body. In the embodiment indicated
schematically in FIG. 1, device 20 is a catheter or other flexible
elongated or tubular housing or member 22 having an application end
with a wall 24 defining an internal chamber 26, with catheter 22
being sized and configured in a particular example for insertion
into and/or travel along the vascular system. Within catheter 22
and chamber 26 in this embodiment is a transducer 28 for sending
and/or receiving ultrasound signals. In particular embodiments, one
motor 30 may be provided, connected directly or indirectly to
transducer 28 so as to turn transducer 28 around a longitudinal
axis of device 20, pivot transducer 28 around an axis substantially
perpendicular to that longitudinal axis, and/or provide other
motions to transducer 28. As discussed further below, one or more
motors 30 (e.g. two motors 30a and 30b indicated in the illustrated
embodiments) may be provided within catheter or housing 22 and are
connected directly or indirectly to transducer 28 so as to turn
transducer 28 around a longitudinal axis of device 20, pivot
transducer 28 around an axis substantially perpendicular to that
longitudinal axis, and/or provide other motions to transducer 28.
Another example of the indirect connection of a motor to transducer
28 noted above would be via a torque cable, and in such case a
coupling or coupling and bearing for the cable could be present in
the location of one or both motors 30a, 30b, rather than such
motor(s). The coupling or coupling and bearing (like the motor(s))
would provide motion to parts as discussed further below.
Catheter 22 in the illustrated embodiment is an elongated device of
plastic or other sturdy flexible material that is substantially
transparent to or presenting a minimal barrier to passage of
ultrasound signals. For example, when used within a blood vessel
containing body tissues and blood, it is preferable for catheter 22
(or at least some or all of wall 24) to be constructed of a
material which has an acoustic impedance similar to that of body
fluids such as blood. Possible materials could include, for
example, a polymer material such as high density polyethylene
(HDPE), polymethylpentene (PMP), or acrylonitrile butadiene styrene
(ABS). It has been determined that a preferred thickness of at
least the portion of catheter 22 which serves as the viewing window
is approximately 1/2 of the wavelength corresponding to center
frequency.
Wall 24 surrounds chamber 26, which is at the distal end of device
20 in the illustrated embodiment, and extends proximally. Wall 24
is a monolithic part of a catheter 22 in some embodiments, and in
others wall 24 is at the application end surrounding all or part of
chamber 26. Wall 24 may extend toward the control end of device 20
beyond chamber 26 in some examples. The proximal end of wall 24
and/or catheter 22 may extend outside of the patient during use,
and the control end may include a handle or other operating portion
(e.g. an imaging system and/or a maneuvering system (not shown)).
Particular embodiments of catheter 22 or at least chamber 26 are
cylindrical, and are sized for insertion into and passage through
blood vessels, such as insertion into the femoral artery and
passage through it toward the heart.
Transducer 28 is indicated schematically in the drawings. The term
"transducer" should be understood to include an assembly of two or
more parts as well as a single piece. For instance, transducer 28
can include a body or backing 40 with a transducer element 42
attached to one side of body 40, and a matching layer (not shown)
attached to one side of element 42. The matching layer is attached
to one side of element 42 and may be focused or non-focused. The
matching layer has acoustic impedance generally between that of
element 42 and the medium surrounding transducer 28 in order to
minimize mismatched acoustic impedance between transducer 28 and
the medium surrounding transducer 28 (e.g. mineral oil). In some
embodiments, transducer 28 includes an element 42 and matching
layer but no body 40. In this embodiment, transducer 28 is
pivotable and/or rotatable through action or influence of motor 30,
so that with element 42 on the side of body 40 as indicated, a
generally lateral (i.e. away from the longitudinal axis) and
forward ultrasound beam direction is possible depending on the
motion of transducer 28. Embodiments of transducer 28 may be
capable in particular examples of sending and receiving ultrasound
waves in a range of frequencies which are typically used in medical
ultrasound procedures, such as, for example, in the range from 2
MHz to 50 MHz.
Transducer 28 is electronically connected to a power source and to
an imaging system (not shown). Examples of connections include
conductors (e.g. wires or cables) along wall 24, through a central
lumen of a motor shaft, via slip ring connections, and/or via
metallic film(s) along wall 24. Transducer 28 may be mounted in a
pivoting mechanism or otherwise linked to motor 30 or a shaft 44
(which rotates, travels longitudinally, or otherwise moves) to
permit transducer 28 to turn, pivot, or otherwise move. Embodiments
of such examples are discussed and shown in application Ser. Nos.
61/713,135; 61/713,172; 61/714,275; and 61/748,773, all of which
are incorporated by reference in their entireties.
Motor 30 may be a rotary or linear motor and includes a shaft 44
for connecting or linking to transducer 28 or a mechanism connected
to it. In the illustrated embodiments, a rotary motor 30a and a
linear motor 30b are provided, with respective shafts 44a and 44b.
Motor 30a turns hollow shaft 44a about a longitudinal axis L of
device 20, and shaft 44a is linked to transducer 28 as
schematically indicated so that transducer 28 likewise turns around
axis L. Motor 30b moves shaft 44b forward and backward along axis L
and through shaft 44a in this example, with shaft 44b engaging or
linked (not visible in FIG. 1) to transducer 28 off-center. Forward
motion of 44b tends to pivot transducer 28 clockwise about an axis
into the page (perpendicular to axis L), and rearward motion of
shaft 44b tends to pivot or allow pivoting of transducer 28
counterclockwise around an axis into the page.
Embodiments of piezoelectric or electromagnetic micromotors of a
size and configuration suitable for containment within catheter 22
may be used. For example, a particular embodiment of a rotary motor
(e.g. motor 30a) is a two-phase, coreless, brushless DC
electromagnetic motor, which has few components, small size and
minimal complexity. A piezoelectric micromotor is of a small size,
such as having a diameter in the range from 0.3 mm to 4 mm in
particular embodiments, and can exhibit a high torque-to-size
ratio. An example of a linear motor (e.g. motor 30b) is an
electromagnetic motor similar to a voice coil, used extensively for
loudspeakers, which operate by creating a high static magnetic flux
(e.g. by a permanent magnet) in the lateral direction (e.g.
perpendicular to the longitudinal axis of the motor). An
electrically conductive coil is placed through this flux and when
current is applied to the coil a force in the axial direction is
created, pulling or pushing shaft 44b.
One or more seals 50 may be provided. For example, respective
seal(s) 50 are provided in this embodiment forward of motor(s) 30
(e.g. engaging or adjacent to the forward-most part of each of
motors 30a and 30b in the illustrated embodiment) to separate
chamber 26 from motor 30. Seal 50 in the illustrated embodiment is
a wall or membrane that extends across the entire diameter or width
of the space within wall 24, e.g. chamber 26. Seal 50 may be
unitary, formed with wall 24 and of the same material as wall 24,
or may be separately formed and inserted into and joined with the
inside of wall 24. As indicated in the drawings, one or more shafts
(e.g. shafts 44a and/or 44b, associated with motors 30a and/or 30b)
extend through seal 50 in order to link or connect to transducer
28. In such embodiments, a seal 50 thus provides not only a general
wall bounding chamber 26, but seal(s) 50 also inhibit or prevent
flow of fluid out of chamber 26 and/or around shaft(s) 44 extending
through seal(s) 50. Particular configurations and examples of seals
are shown in application Ser. No. 61/787,357, entitled "Internal
Ultrasound Assembly Fluid Seal" and filed on Mar. 15, 2013, which
is incorporated herein by reference in its entirety.
Wall 24 in the illustrated embodiments includes features to permit
easy and effective injection of a coupling medium into chamber 26.
In the embodiment shown in FIGS. 1-2, an injection port 60 is
provided in a portion of wall 24, as is an exhaust port 62.
Injection port 60 in this embodiment is an insert sealingly fitted
into wall 24, i.e. the insert is fitted in wall 24 so that any
border between them is at least substantially leak-tight. The
insert in particular embodiments has self-sealing properties. In
other embodiments, injection port 60 may be formed in or along with
wall 24, or if wall 24 is made of a suitable material, injection
port 60 may simply be a portion (or any portion) of wall 24
surrounding chamber 26. The material of injection port 60 in
particular examples is a natural or synthetic rubber or rubber-like
material, which is easily pierced by a thin needle and which, when
the needle is removed, resiliently closes or collapses the hole
made by the needle so as to provide a leak-tight seal. Other
materials may be used, beyond those that can be pierced by a needle
and self-seal. The example of port 60 as shown is substantially
disc-shaped and is fixed in wall 24. In particular embodiments,
port 60 is at least substantially immobile in rotation and/or in
translation with respect to wall 24 once placed. Turning or
removing such a port may have deleterious effects on the
surrounding wall 24 or other parts of device 20.
Injection port 60 is shown in the illustrated example at the
forward-most point (i.e. the insertion end) of device 20. Such
placement has the advantage, in devices in which transducer 20 is
both rotatable around axis L and pivotable around an axis
perpendicular to axis L, of locating injection port 60 in an area
of lesser or least interference with visualization or other
application of ultrasound waves from transducer 28. Placement of
injection port 60 in a side portion of wall 24 (lateral of axis L)
would locate it more directly in the sweep path of ultrasound
energy traveling to and/or from transducer 28, generating a side
blind spot. Thus, in particular embodiments injection port 60 is at
a location not faced by the transducer, where such location is
possible.
Exhaust port 62 in this embodiment is a valve fitted or placed in
wall 24 in fluid communication with chamber 26. As with injection
port 60, exhaust port 62 may be an insert (e.g. a valve) sealingly
fitted into wall 24, i.e. the valve or other insert is fitted in
wall 24 so that any border between them is at least substantially
leak-tight. In other embodiments, exhaust port 62 may be formed in
or along with wall 24 (e.g. a conical or otherwise narrowing
passage through wall 24, having its narrowest point at the exterior
of wall 24). In such an embodiment, a valve may also be placed in
or along the passage, such as at or adjacent the location where
port 62 meets chamber 26, or at or adjacent the location where port
62 meets the exterior of wall 24. Exhaust port 62 preferably allows
gas to move from chamber 26 through port 62 to the outside of
device 20 during filling or charging of chamber 26 with coupling
medium, but to seal against entrance of gases or liquids from the
outside into chamber 26. Exhaust port 62 is shown in the
illustrated example at a rearward-most point of chamber 26, i.e.
adjacent to seal 50, and in this embodiment substantially opposite
to the placement of injection port 60. As with the placement of
injection port 60, such placement locates exhaust port 62 in an
area of lesser or least interference with visualization or other
application of ultrasound waves from transducer 28, avoiding a side
blind spot toward the middle of the acoustic window of wall 24
around chamber 26. In particular embodiments, exhaust port 62 is at
a location not faced by the transducer, where such location is
possible. It will also be noted that in embodiments in which
motor(s) 30 are electromagnetic motors and the coupling medium
chosen does not adversely affect such a motor, exhaust port 62 may
be placed through seal 50 or in a similar location to exhaust gas
and any fluid that may escape from port 62 through seal 50 and/or
the motor(s) (see FIG. 1A). As noted previously, if any motor 30 is
piezoelectric, exhaust port 62 should ensure that exhaust gas and
escaping fluid is routed around or away from the motor.
As noted above, port 62 can be a passage formed in wall 24. As one
example, FIG. 1B shows port 62 as a channel or groove in wall 24
leading to an open space or compartment. The open space may be
behind one or more motors, if present, or as discussed previously
may exhaust into or through a motor. The channel or groove may be
molded, cut, extruded or otherwise formed into wall 24 so that air
can travel from chamber 26 when displaced by coupling medium.
In use, this embodiment of device 20 is charged or injected with a
coupling medium prior to initial insertion into the body. An
appropriate coupling medium is selected, such as saline, oils,
alcohols or other appropriate acoustic coupling fluids. The
coupling medium is loaded into a syringe with a needle (not shown)
or other appropriate injection device. Using the syringe with
needle as a particular example, the needle is inserted through
injection port 60, so that the open tip of the needle is within
chamber 26. The coupling medium is then forced through the needle
and into chamber 26, as by pressing a syringe plunger. As the
coupling medium enters chamber 26, it increases the pressure on the
gas (e.g. air) within chamber 26. The increased pressure forces the
gas out of chamber 26 through exhaust port 62. Injection of
coupling medium continues until chamber 26 is filled to a
satisfactory degree, for example when a maximum amount of the gas
previously in chamber 26 has been replaced with coupling medium. An
optimum result would be to have the entire chamber 26 filled with
coupling medium, so that no visible gas pockets or bubbles are
present, as gas pockets or bubbles have an acoustic impedance
significantly different from the coupling medium, and thus can
reflect or otherwise attenuate ultrasound waves.
It is generally desirable to limit or eliminate the opportunity for
gas pockets to form within chamber 26. Accordingly, in one example,
during the injecting, the user may have device 20 oriented so that
exhaust port 62 is oriented or points generally upward, so that it
is at or near the vertically highest location of wall 24. With that
orientation, coupling medium will generally pool away from exhaust
port 62, naturally maintaining gas within chamber 26 between the
pool of coupling medium and exhaust port 62. In another example,
some or substantially all of gas within chamber 26 may be removed
prior to injection of coupling medium, as by evacuating through
application of vacuum directly or indirectly to port 62. Little or
no gas remains to be evacuated via the pressure of the coupling
medium.
Once charged with coupling medium, device 20 is inserted into the
patient, for example into the patient's vascular system, and is
maneuvered to the desired location. The desired therapeutic,
diagnostic, imaging or other ultrasound procedure is performed, and
the device can be removed. Having injected the coupling medium
shortly or immediately prior to use of device 20, the chance of
improper operation of device 20 due to corrosion of parts by the
coupling medium or seepage through seals is minimized.
In another example, indicated schematically in FIG. 3, injection
port 60' and exhaust port 62', each in fluid communication with
chamber 26, are shown as respective lumens traveling along at least
a portion of device 20, and having respective openings in chamber
26. For instance, injection port 60' may be or include a tube 70
having a lumen 72 therethrough and a forward end opening 74 that
communicates with chamber 26. In this example, a portion of tube 70
is within wall 24 around seal 50 and motor(s) 30, and tube 70 can
travel within or along (e.g. fixed to) the interior surface of
catheter 22 when between motor(s) 30 and the handle or operating
end (not shown) of device 20. It will be understood that in other
embodiments a tube 70 may extend from the handle or operating end
(or from a location between the handle or operating end and
motor(s) 30) to a lumen formed in wall 24, with such lumen
extending through wall 24 outside of motor(s) 30 and opening into
chamber 26. Further, embodiments in which tube 70 is part or all of
a lumen of or within catheter 22 (e.g. a dedicated lumen of
catheter 22, or a lumen extending within the wall of catheter 22 to
a location at or near the operating end) are also contemplated. One
or more valves 76 may be placed in or over tube 70, e.g. at the
interface between tube 70 and chamber 26, to allow fluid to enter
chamber 26 from tube 70 but not to escape chamber 26 into tube
70.
In a similar fashion, this embodiment of exhaust port 62' may be or
include a tube 80 having a lumen 82 therethrough and a forward end
opening 84 that communicates with chamber 26. In this example, a
portion of tube 80 is within wall 24 around seal 50 and motor(s)
30, and tube 80 can travel within or along (e.g. fixed to) the
interior surface of catheter 22 when between motor(s) 30 and the
handle or operating end (not shown) of device 20. In some
embodiments, a tube 80 may extend from the handle or operating end
(or from a location between the handle or operating end and
motor(s) 30) to a lumen 82 which extends through wall 24 outside of
motor(s) 30 and opens into chamber 26, as noted above with respect
to injection port 60'. Further, embodiments in which tube 80 is
part or all of a lumen of or within catheter 22 (e.g. a dedicated
lumen of catheter 22, or a lumen extending within the wall of
catheter 22 to a location at or near the operating end) are also
contemplated. As indicated in FIG. 3, a particular embodiment has
injection port 60' and exhaust port 62' diametrically opposed to
each other in device 20. One or more valves 86 may be placed in or
over tube 80, e.g. at the interface between tube 80 and chamber 26,
so as to permit exit of gas and/or liquid from chamber 26 into tube
80, and to prevent re-entry of gas or liquid into chamber 26 from
tube 80.
As noted above, port 62' can be all or part of a lumen in the wall
of catheter 22. As one example, FIG. 3A shows port 62' as a channel
or groove in wall 24 leading to an open space or compartment. The
open space may be behind one or more motors, if present, or as
discussed previously may exhaust into or through a motor. The
channel or groove may be molded, cut, extruded or otherwise formed
into wall 24 so that air can travel from chamber 26 when displaced
by coupling medium. As with examples noted previously, channel 62'
provides a passage for air to an open area or chamber where the air
can be accepted or compressed into.
One or both of ports 60' and 62' may be located similarly to the
placement of exhaust port 62, such as at a rearward-most portion of
chamber 26. Such placement locates port(s) 60' and/or 62' in an
area of lesser or least interference with visualization or other
application of ultrasound waves from transducer 28. In particular
embodiments, one or both of injection port 60' and exhaust port 62
are at a location not faced by the transducer, where such location
is possible.
Charging this embodiment of device 20 with a coupling medium can
occur prior to initial insertion into the body, or at any time
after device 20 is within the body. Once an appropriate coupling
medium is selected, a supply of it (e.g. in a syringe (not shown)
or other appropriate supply device) is connected to tube 70. In
embodiments in which tube 70 extends out to a handle or operating
portion (not shown) of device 20, the syringe or other supply may
be connected to tube 70 in or adjacent to such operating portion.
The coupling medium is forced through tube 70 and lumen 72 into
chamber 26, as by pressing a syringe plunger or operating a pump.
As the coupling medium enters chamber 26, it increases the pressure
on the gas (e.g. air) within chamber 26. The increased pressure
forces the gas out of chamber 26 through exhaust port 62', e.g.
through opening 84 and into lumen 82 of tube 80. Injection of
coupling medium continues until chamber 26 is filled to a
satisfactory and/or optimum degree, as described above. As
previously noted, as a way to help limit or eliminate the
opportunity for gas pockets to form within chamber 26, during the
injecting the user may have device 20 oriented (to the extent
practical in a given situation) with exhaust port 62', and
particularly opening 84, generally upward, so that it is at or near
the vertically highest location of wall 24. With that orientation,
coupling medium will generally pool away from opening 84, naturally
maintaining gas within chamber 26 between the pool of coupling
medium and opening. In some embodiments, gas from the chamber can
be evacuated prior to insertion or injection of coupling medium,
rather than by the pressure of the applied coupling medium. For
example, a source of vacuum can be applied to tube 80, to withdraw
gas through port 62', and then coupling medium can be added to
chamber 26 via tube 70.
Once charged with coupling medium, device 20 is inserted into the
patient, for example into the patient's vascular system, and is
maneuvered to the desired location. The desired therapeutic,
diagnostic, imaging or other ultrasound procedure is performed, and
the device can be removed. Having injected the coupling medium
shortly or immediately prior to use of device 20, the chance of
improper operation of device 20 due to corrosion of parts by the
coupling medium or seepage through seals is minimized.
The arrangement of ports 60, 62 does not require as much space in
the wall or around the motor(s) 30, as is needed for the placement
of tubes 70, 80 of ports 60', 62'. Such space considerations can be
quite important for uses of ultrasound in small areas, such as
cardiovascular (e.g. peripheral vascular) applications. As will be
appreciated, ports 60', 62' provide the ability to charge chamber
26 with coupling medium in situ, rather than charging and then
inserting device 20. Confirmation of the orientation of a device 20
with ports 60', 62' may be necessary if it is desired to maintain
port 62' in an upward location during charging.
It will be understood that parts of the embodiments noted above can
be interchanged with each other. For example, an embodiment of
device 20 could include an injection port 60 and an exhaust port
62', or an embodiment of device 20 could include an injection port
60' and an exhaust port 62.
While the embodiments have been illustrated and described in detail
in the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it
being understood that only particular embodiments have been shown
and described and that all changes and modifications that come
within the spirit of the disclosure are desired to be protected. It
will be understood that features or attributes noted with respect
to one or more specific embodiments may be used or incorporated
into other embodiments of the structures and methods disclosed.
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